Authorities in the U.S. are investigating whether police in a town dominated by one of the nation's largest polygamous sects prevent women from leaving the church run by imprisoned leader Warren Jeffs.

Arizona Attorney General Tom Horne on Tuesday said the probe involves the town of Colorado City, the home base of the Fundamentalist Church of Jesus Christ of Latter Day Saints.

The criminal investigation mirrors the one that landed Jeffs in prison in one of the largest custody cases in U.S. history. Jeffs, who is said to still rule the sect, is imprisoned for life in Texas after convictions on child sex and bigamy charges.

Horne declined to provide details of the criminal investigation of the FLDS and the Marshal's Office, which serves as a small police force in the twin polygamous towns of Hildale, Utah, and Colorado City.

“Women who wanted to escape have been forcibly held by the marshals against their will,” Horne said.

“I can't speak for the FLDS, but the bottom line is the Marshal's Office absolutely does not hold people against their will,” said lawyer Blake Hamilton. “The Arizona attorney general, as the highest-ranking law enforcement official in Arizona, ought not be making those statements unless he has evidence of it.”